net: phy: micrel: Update Kconfig help text

net: phy: micrel: Update Kconfig help text

This driver by now supports 17 different Microchip (formerly known as
Micrel) chips: KSZ9021, KSZ9031, KSZ9131, KSZ8001, KS8737, KSZ8021,
KSZ8031, KSZ8041, KSZ8051, KSZ8061, KSZ8081, KSZ8873MLL, KSZ886X,
KSZ9477, LAN8814, LAN8804 and LAN8841.

Support for the VSC8201 was removed in commit 51f932c4870f ("micrel phy
driver - updated(1)")

Update the help text to reflect that, list families instead of models to
ease future maintenance.

Signed-off-by: Jonas Rebmann <jre@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250911-micrel-kconfig-v2-1-e8f295059050@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>